I recently moved and when I went to reconnect my AV setup, everything is working fine except for the ep350 sub. It continuously makes a humming noise no matter what volume I use on the sub. The sub is connected to receiver with just the preout RCA plug, same exact wire I had previously used that was working, now it makes the humming noise. I've replaced the sub with a KEF powered sub, using the same wire and it works fine, no humming. The sub does play sound and bass, so it works, but continues to hum no matter what output level.

I've tried playing with all the settings on the receiver, speaker setup, different wires, even using the preout from the KEF sub to the Axiom sub and still the humming? Any thoughts, did the sub just run its course, amp messed up on the sub? This is driving me nuts?!?!?!

Update:

Moved the sub to my other onkyo receiver in another room, where the KEF is normally plugged in and it still hums. Tried replacing the power strip, no changes. I'll try a ground loop isolator tomorrow?

Gog, welcome. The fact that the hum existed when plugged into outlets in different rooms raises at least a possibility that this isn't a ground loop hum. If you disconnect the sub cable(while it's humming)and just have the power cord as the only connection, does the hum still exist? If so, there's no connection to form a path for a ground loop, and the problem is in the sub amp. If not, the next thing to try would be removing the chassis ground screw on the back of the sub amp.

Gog, apparently the Axiom site info is outdated or simply incorrect as to the recent EP350s. It continues to both illustrate and suggest the use of the "Chassis Ground" screw in cases of possible ground loop hum.

Using a "cheater plug" will certainly stop the hum, but the absence of the previous chassis ground screw raises a question as to whether there'd be an alternate ground through the sub cable or if there'd be none at all if the ground through the sub power cord is defeated. Axiom should clarify this.

Yes, disconnect the satellite cable to see if that's the link in the ground loop. The Axiom ground loop unit isn't suitable for satellite TV use since it would interfere with signals to the dish.